Johnson HD 25 What Year?

[CRFricke]

I have recently become the owner of a Johnson HD 25. It is serial number 300551. What year is it and where does one find the list of serial numbers and years for these old Johnsons?

Also it starts well, but has problems starting when it is warm. I have heard that these have a problem with vapor lock, any ideas or suggestions would be greatly appreciated.

Thanks,

Chuck in Traverse City

 

[175se]

Welcome Chuck ! The hd 25 is the model# ( 1946-50 )2.5 hp. There used to be a little book that had the info on model #s.

 

[CRFricke]

Dear 175se. Yes I have Mr. Hunn's Old Outboard Book. I am looking for the specific year of this engine. I see other posts that give serial number ranges for each year for the HD 25. Any help would be appreciated.

Also this engine has a primer that squirts fuel into a Y connection at the front of the engine. This Y connection has what appears to be a high or low speed adjustment. What is this and how does one adjust it?

Thanks,

Chuck

 

[F_R]

That is the slow speed air/fuel inlet. Leads to a rotary valve inside. The needle is the slow speed mixture adjustment and is very sensitive. Should be very close to 5/8 turn open.

You are correct, they are prone to fuel boiling and vaporizing in the carburetor if overheated. So a well operating water pump is necessary.

The serial number ranges are listed in Hunn's book. At least they are in the version I have. But your number comes in as a 1938 which isn't right. Recheck your number.

 

[CRFricke]

Dear FR:

Thanks for the information. I clearly don't have the right number, keep in mind that I may not have the right model. I can find no serial or model numbers on this motor. I found the 300551 on the head, in the center between the plugs. I have a 5 hp, 1953 and this motor is MUCH lighter. It appears to be a HD 25 based up my comparison with some on line photographs.

Where should I be looking for the Model and Serial numbers?

Thanks for all that you do,

Chuck

 

[CRFricke]

Dear FR:

Regarding the water pump, I pulled the screw below the head and water pulsed out of this hole - squirt - squirt - squirt for about three (3) feet. Does that appear to be functioning properly?

Thanks for all that you do,

Chuck

 

[F_R]

Lessee, if I remember correctly, the numbers are stamped on the cylinder, on side opposite from the carburetor side. At least I know that is true of your TD/TN 5hp.

Yes, your pump is functioning, but I cannot say from here if it is functioning at 100% efficiency. Motor should stay cool at slow idle.

 

[CRFricke]

Dear FR:

I am at a loss. I have been all over that engine and no numbers. Here are a few photos with the cowl off.

Thanks for all that you do,

Chuck

 

[CRFricke]

To all who are following this, I FINALLY found the serial number; that being 745523. Any idea what year this motor is?

Thanks to all,

Chuck

 

[F_R]

1949

 

[CRFricke]

Dear FR:

Thanks, it is now running but not real well. I will take the carb off and clean it.

Thank you very much,

Chuck